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820-00165-A Loud Fan Spin / Slow Operation after Liquid Damage

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  • 820-00165-A Loud Fan Spin / Slow Operation after Liquid Damage

    Initially wouldn't turn on , Ran through ultrasonic cleaner now I am here. No more visible liquid or corrosion on board.

    Current issues - Loud Fan Spin + Slow / Laggy Operation

    Everything Else Works Fine.

    From what I can tell I need to run an "MRI" test as ASD is not available for the 2015 MacBook Airs to determine which sensor(s) are failing.

    Using standard hardware test shows:"may be an issue with smc - PFM006, may be an issue with power management system - PPN001

    How can I run an "MRI" test?

    Any help is much appreciated - thank you!!

  • #2
    Seems that you need to replace LIO board, or/and flex...


    • #3
      Tried this, same results


      • #4
        Did you try known good LIO board and flex?
        If yes, try new trackpad and flex.

        Does it run from battery only?
        Check CHGR_AMON and CHGR_BMON voltage.

        Also check all thermal sensors from page 44...


        • #5
          Yes known good, runs off battery and charger

          Everything normal except high fan spin (4.6V FAN_RT_PWM)

          Thermal sensors appear to test okay, normal voltages compared to known good board - no visible damage.

          I seen in another thread a user with similar issue was recommended to use "MRI" test to determine which sensors are failing by Duke. (Can't seem to find that thread now)


          • #6
            Inspect LIO connector from MLB with microsope...


            • #7
              Looks fine.. starting to wonder if i'm being trolled.

              Tested known good boards with only fan IO Board and IO Flex attached, each with its own parts independent of each other. Only common denominator is the charger I am using but I doubt that has anything to do with fan speed.

              All are starting normal then go to 4.6V high speed fan.. on three separate boards -- is this normal?!


              • #8
                "three separate boards"
                3 LIO boards, or MLB?


                • #9
                  Both, three independent motherboards each with its own known good IO Board & Flex

                  Only thing in common between the three is the external known good charger


                  • #10
                    So I just took the original board with the issue , installed it into the laptop put all screws etc. Fan now runs normal ... seems only high fan speed when board is on its own outside the laptop.. is this normal?


                    • #11
                      MLB requires LIO board and trackpad connected.
                      If not, fan goes high; because correspondent sensors are not found.


                      • #12
                        This makes sense!
                        ​​​​​​Okay thank you.


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